The present invention relates generally to a heat sink which frictionally engages an electronic device such as a semiconductor package for dissipating thermal energy which is generated by the electronic device into the surrounding environment.
Many electronic devices generate heat during their operation. This heat must be dissipated in order to prevent damage to the electronic device. The present invention is specifically directed to an electronic device such as a semiconductor encapsulation package which includes a plastic body with leads extending from one end thereof, and a thermal transfer plate extending from the opposite end of the plastic body. One such semiconductor package is known in the electronic industry as a TO-220 plastic power package. This and similar packages consist of an active semiconductor component which is encapsulated in a plastic body with leads extending from one end of the plastic package and a broad flat thermal transfer plate which is fixed to one major surface of the body and is parallel with the leads.
Typical prior art heat sinks for clamping to electronic devices such as semiconductor packages are stampings of resilient heat conductive and heat dissipating spring metal. The stamping is bent into a structure which has a U-shaped enclosure for receiving and holding a semiconductor package such as a TO-220. The enclosure has a supporting base wall and opposing side walls. The heat sink has an opening to the enclosure and includes resilient fingers or projections for biasing the semiconductor package against the base wall of the heat sink. The heat sink has a hole in the base wall which is to be aligned with a similar hole in the semiconductor package. The heat sink is provided with a stop for locating the semiconductor package within the enclosure of the heat sink that the holes of both bodies are aligned. The sides of the semiconductor package is restrained by the side walls of the heat sink. Since the heat walls of the heat sink are formed by bending, the inside corner of each side wall where it joins the base wall is rounded. If the heat sink enclosure is dimensioned so that the distance between the side walls is equal to the width of the semiconductor package, the semiconductor package is prevented from attaining a flush contact with the base wall because of the rounded inside comers of the enclosure. If the side walls are bent so that the distance between the side walls is greater than the width of the semiconductor package, the semiconductor package will be flush with the base wall. However, this results in an unacceptable sloppy lateral fit of the semiconductor package within the heat sink enclosure.
Another problem which is frequently encountered with clamping heat sinks is the difficulty of inserting an electronic device such as a semiconductor package into and/or out of the enclosure of the heat sink. These and other difficulties encountered with prior art heat sinks are obviated by the present inventions.
It is a primary object of the present invention to provide a clamping heat sink for an electronic device such as a semiconductor package which clamps the electronic device firmly and securely.
Another object of the invention is the provision of a clamping heat sink for an electronic device which is easily applied to the electronic device and which can be easily removed from the electronic device.
A further object of the invention to provide a variant clamping heat sink for an electronic device which is capable of holding a pair of electronic devices.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.